I have been eating mainly grass-fed beef and lamb for awhile now. I bought a quarter cow from a local guy.
When I cook a roast and let it (with the juices) get cold, the fat hardens like butter/ coconut oil type consistency. That hardened fat tastes very good to me and feels very good to eat.
I also have not eaten any grains for quite awhile.
Recently my wife made a roast from a commercial source butcher shop.  When the leftovers got cold, the resulting hard fat tasted off.  I tossed the hardened fat.
Just a personal observation.
-David